Royal Netherlands Institute for Sea Research

Hydrothermal vent fields

Protecting deep seabed hydrothermal vent fields through area-based management tools

The deep seabed is the common heritage of humankind, and is at risk by the imminent start of mining. Trans-disciplinary research within environmental science and international law will assess the role of area-based management tools (ABMTs) in protecting hydrothermal vent fields against mining impacts. We investigate ecological connectivity at vent field scale to determine the necessary dimensions of ABMTs, and how these outcomes are best integrated in the regulatory framework of the International Seabed Authority (ISA). The Netherlands government and others may use the research outcomes to ensure ISA regulation meets the highest possible environmental and biodiversity standards.


The strengthened and trans-disciplinary research and expertise generated by this project will be of value to the Netherlands government and other stakeholders on deep seabed mining

    Erik Molenaar, Sabine Gollner

Project description

The imminent start of mining poses risks to hydrothermal vents, including habitat removal, vent-fluid change, toxic mining plumes, and associated risks of biodiversity loss. Several intergovernmental organizations suggest that active vents classify as areas in need of conservation. The international community has adopted commitments and targets on using ABMTs for conservation (e.g. UN Sustainable Development Goals) and legal obligations will be included in the ‘BBNJ Agreement’ under the UN Convention on the Law of the Sea that is currently under negotiation.

The dimensions of ABMTs are of key importance for their ability to protect vents against external mining impacts. An active vent field is a spatially associated cluster of active and inactive chimneys/mounds. Mining impacts may damage active and inactive vents, nonhydrothermal sediments and the benthic and pelagic surroundings within and beyond a vent field. Most environmental research has focused on active chimneys. Unknown, however, is the ecological connectivity between active chimneys and their benthic and pelagic surroundings. Focused research on this connectivity is required to determine the necessary three-dimensional size of ABMTs.

Optimizing ABMTs in terms of operational effectiveness must be supplemented by optimizing regulatory effectiveness through integrating ABMTs in the ISA’s regulatory framework. ISA regulations refer to various types of ABMTs (e.g. Impact reference zones and Preservation reference zones). It is not clear, however, if these can be used and are suitable for the envisaged 3-dimensional ABMTs to protect vents and, if not, what the opportunities and constraints of alternative options are. This requires in-depth international law research on ISA’s regulations, founding instruments and other relevant international instruments (e.g. the BBNJ Agreement) and best practices thereunder.

Main goals

  1. Contribute novel data on the ecological role of active chimneys for the vent field and beyond and vice versa, through the use of samples collected on vent fields at the Mid Atlantic Ridge.
  2. Assess whether the ISA’s existing ABMTs can be used and are suitable for ABMTs determined as optimal (under goal 1 above) and, if not, what the opportunities and constraints of alternative options are.
  3. Collaborate with representatives from governments, the ISA, the industry and NGOs, so that stakeholders may use our results to progress plans for mining in an environmentally sustainable manner.
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The imminent start of mining poses risks to hydrothermal vents, including habitat removal, vent-fluid change, toxic mining plumes, and associated risks of biodiversity loss. Photo NIOZ


Stakeholder event: Current developments on deep seabed mining and the use of area-based management tools to protect hydrothermal vents

Date 10 May 2023

A wide range of stakeholders attended the event, including academics and representatives from non-governmental organizations (NGOs), industry, and government. The event had two sessions: the first presented different perspectives of deep seabed mining and engaged in discussions around the call for a deep seabed mining moratorium / precautionary pause; the second concerned protecting hydrothermal vents from the harmful effects of deep seabed mining and focused on concrete action that could be taken to ensure their protection.

Report and speaker's slides


Workshop: Non-use measures for global goods and commons in international law

Date: 8-9 May 2023

Most resource management measures at the international level focus on the conditions under which use of some resources is allowed. In certain cases, however, States decide to adopt and implement non-use measures: measures that ban a certain use altogether or restrict (certain types of) use in certain areas. With the increasing pressure on natural resources, in particular those considered global goods and commons, and in order to implement the precautionary approach, non-use measures might need to be further promoted and adopted. To investigate this theme further, a workshop was held at Utrecht University on 8-9 May 2023, specifically addressing these four topics: the high seas, Antarctica, deep-sea mining, and the atmosphere and outer space.

Workshop report

Workshop: Protecting deep seabed ecosystems under the future Agreement on the Conservation and Sustainable Use of BBNJ and by the ISA – Perspectives of Government, Civil Society, Stakeholders, and Law and Science

Date: 13-15 December 2021

The workshop aims to bring together a wide variety of stakeholders and researchers to discuss the role of ABMTs under various international processes and organizations. The event is organized by the Netherlands Institute for the Law of the Sea (NILOS), the Utrecht Centre for Water, Oceans and Sustainability Law (UCWOSL) of Utrecht University, and the Netherlands Ministry of Foreign Affairs, in collaboration with the Royal Netherlands Institute for Sea Research (NIOZ)

Programme of the Workshop

More information and speakers' slides


  1. C Blanchard, E Harrould-Kolieb, E Jones and ML Taylor (2023). The current status of deep-sea mining governance at the International Seabed Authority. Marine Policy, 147, 1-9. [105396], available here.
  2. C Blanchard and S Gollner, ‘Area-based management tools to protect unique hydrothermal vents from harmful effects from deep-sea mining: A review of ongoing developments’ (2022) 4 (1033251) Frontiers in Political Science 1 – 16, 10.3389/fpos.2022.1033251, available here (comments and review by Erik Molenaar)
  3. C Blanchard, ‘Nauru and Deep-Sea Minerals Exploitation: A Legal Exploration of the 2-Year Rule’, The NCLOS Blog on 17 September 2021, available here.
  4. S Robb, ‘Bolstering the Area’s Benefits to Humankind: A Legal Analysis of UNCLOS’ Common Heritage of Mankind Principle and ‘for the benefit of mankind’ Provisions in the Context of the Call for a Deep Seabed Mining Moratorium’ The NCLOS Blog on 28 February 2023, available here (comments and review by Erik Molenaar and Catherine Blanchard)
  5. S Robb, A Jaeckel, C Blanchard, ‘How could the BBNJ Agreement affect the International Seabed Authority’s Mining Code?’ EJIL:Talk! On 13 April 2023, available here.
  6. E Harrould-Kolieb, C Blanchard, ‘The Fraught Governance of Deep-Sea Mining.’ (2022), available here.

Connected themes

  • Sunstainable functioning of Coastal and Shelf Seas
  • Ocean of Discovery
  • Our Future Ocean 
NIOZ project page